This study examined the acute effects of hamstring and calf static stretching on peak torque and the rate of velocity development during leg flexion muscle actions at 60, 180, and 300°/sec in Ss of both genders. Women (N = 13) and men (N = 15) performed three maximal voluntary isokinetic leg flexion actions at three randomly-ordered velocities (60, 180, and 300°/sec) before and after a bout of hamstring and calf static stretching. The stretching consisted of one unassisted and three assisted static stretching exercises designed for the posterior muscles of the thigh and leg. Four repetitions of each stretch were held for 30 seconds with 20 seconds of rest between repetitions.

Peak torque decreased (-7.5%) as a result of the stretching, but only for the women. There were no changes for the men. There were no other stretching-related changes for peak torque or rate of velocity development. Peak torque and rate of velocity development decreased as the speed of movement increased. These findings suggested that the stretching-induced torque deficits experienced by the women were unrelated to the mechanisms that influence the rate of velocity development.

Implication. Static stretching causes a decrease in leg flexion peak torque for the women, but not for men. Rate of velocity development is not affected by static stretching.